I'm trying to understand the same day confirmed fee and Medallion fee waiver.

There is a $75 fee for a same-day change. But, since the same-day change only allows you to switch if the same fare class as your paid ticket is available, isn't that change free for all tickets except Basic Economy? What exactly are you getting for the $75 fee? And what is the Medallion waiver waiving? Presumably that same $75 fee for a transaction that is supposed to be free?

Here's the page at delta.com: https://www.delta.com/us/en/change-c...-flight-change